1. Field of the Invention
The present invention relates to an irregular pattern input device used for directly inputting an irregular pattern formed on a surface of a flexible material such as a rubber stamp, or a fingerprint into processors or the like.
2. Description of the Prior Art
FIG. 1 shows a conventional irregular pattern input device disclosed in, for example, Japanese Patent Application Laid-Open No. 55-13446. In FIG. 1, reference numeral 1501 means a parallel luminous flux emitted from a light source, and 1502 is a rectangular prism. The rectangular prism 1502 is provided with an entrance surface 1502a and an exit surface 1502band the entrance surface 1502a and the exit surface 1502b are disposed at right angle to each other. Further, reference numeral 1503 means a camera, 1504 means a processor, and 1505 is a subject.
A description will now be given of the operation. The parallel luminous flux 1501 emitted from the light source enters the entrance surface 1502a of the rectangular prism 1502. In this case, the parallel luminous flux 1501 enters perpendicular to the entrance surface 1502a. Further, the subject such as a finger 1505 closely contacts an inclined surface 1502c interposed between the entrance surface 1502a and the exit surface 1502b. In this case, a tilt angle of the inclined surface 1502c with respect to the parallel luminous flux 1501 is adjusted to be no less than a critical angle. Thus, the parallel luminous flux 1501 entering the entrance surface 1502a is totally reflected from a portion of the inclined surface 1502c in no close contact with the finger 1505, and is not totally reflected from a portion of the inclined surface 1502c in close contact with the finger 1505. Thereby, a stripe pattern is generated according to irregularity of the fingerprint formed on the finger 1505. Subsequently, the stripe pattern is inputted into the processor 1504 through the camera 1503.
Since the conventional irregular pattern input device is provided as set forth above, the parallel luminous flux 1501 emitted from the light source is disposed substantially perpendicular to an optical axis of the camera 1503. As a result, there are several problems such as difficulty of downsizing the irregular pattern input device due to restriction on an optical path.